Alternate timeline (The Book of the War)
From Tardis Wiki, the free Doctor Who reference
Faction Paradox claimed that their iconic ceremonial armour was made from the bones of vampirised Homeworlders from an alternate timeline where the Yssgaroth won the war and corrupted their fallen enemies. However, the Houses denied this claim (in line with their insistence that alternate timelines didn't exist), and even Faction experts on the Yssgaroth thought there may be more to the story. At any rate, the bones were sourced from an "abomination's graveyard" accessed by the Godfather-lieutenants of the Grandfather through the caldera. (PROSE: The Book of the War)